Attention-Deficit Hyperactivity Disorder (ADHD) is probably the most commonly diagnosed condition of childhood and accounts for approximately half of all referrals to child mental health clinics. In spite of this, little research has been done to describe, to study possible types, and to treat this disorder in Hispanic groups. Cultural factors can act to shape the manifestation of ADHD in Hispanic children somewhat differently than in Caucasian children Thus. the findings from the extensive anglo research literature on ADHD are not necessarily generalizable to Hispanics and other ethnic groups. Equally uncertain is whether commonly used treatments for ADHD are culturally sensitive and ecologically valid for other ethnic groups. To address these issues the present application proposes to: (1) conduct a comprehensive assessment of 6 to 11 year-old Puerto Rican children with a diagnosis of ADHD, (2) to evaluate whether subtyping ADHD on the basis of the degree of overactivity is meaningful and whether these resulting ADHD types constitute separate distinct disorders, and (3) to design, implement, and revise a treatment program for these children. In the first study, an empirical approach will be used to classify 45 children as Attention Deficit Disorder with Hyperactivity (ADD+H) and 45 children without Hyperactivity (ADD-H). These children will be required to meet a DSM-IV diagnosis of ADHD and to be statistically deviant only on inattention (ADD-H) or on inattention and hyperactivity-impulsivity (ADD+H) teacher rating scores. These two groups will be compared with control groups of underachieving (n=30) and normal (n=30) children, who will have teacher rating scores within the normal range. The measures will address to the patterns of psychiatric comorbidity, severity of behavioral and emotional disturbance, peer relationship problems, academic achievement deficits, selected neurocognitive processes, parental psychosocial maladjustment, and overt behaviors in a laboratory setting. In the second study, a culturally appropriate treatment will be adapted and developed for Puerto Rico ADHD children based on the results of Study 1. This treatment will be implemented, evaluated, and revised based on an open clinical trial of 16 ADD+H and ADD-H children. The results should provide important information on the manifestation and treatment of ADHD in a non-majority ethnic group in the United States.